from django.db import migrations, models


def backfill_state(apps, schema_editor):
    """Items at quantity 0 are 'out'; everything else is 'in' (the field default)."""
    PantryItem = apps.get_model("kitchen", "PantryItem")
    PantryItem.objects.filter(quantity=0).update(state="out")


class Migration(migrations.Migration):

    dependencies = [
        ("kitchen", "0002_add_rating_and_preferences"),
    ]

    operations = [
        migrations.AddField(
            model_name="pantryitem",
            name="state",
            field=models.CharField(
                choices=[("in", "In stock"), ("low", "Running low"), ("out", "Out")],
                default="in",
                max_length=10,
            ),
        ),
        # Runs while quantity is still a Decimal column — 0 matches fine.
        migrations.RunPython(backfill_state, migrations.RunPython.noop),
        migrations.AlterField(
            model_name="pantryitem",
            name="quantity",
            field=models.PositiveIntegerField(
                blank=True,
                help_text="Optional rough count; In/Low/Out is the primary signal",
                null=True,
            ),
        ),
        migrations.AlterField(
            model_name="pantryitem",
            name="unit",
            field=models.CharField(blank=True, max_length=20),
        ),
    ]